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Big Dog
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About Macktech689

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  1. Macktech689

    Truck won't start 08 Granite

    Replace fuse F7 in the BEC.
  2. Macktech689

    Ground relay

    That is a circuit breaker that protects against system damage it there is a battery short to ground. Personally I would not bypass it.
  3. Macktech689

    A/C not working

    Fuse 41 is in the EPDM outside on the firewall, it's a mini fuse, right side 3rd from the top. Marked fan clutch 15a. If that is the fuse with no power, it comes off power relay #3 inside the cab behind the glove box area.
  4. Macktech689

    A/C not working

    Voltage to the APADS also comes from fuse 41 ( 15a ) down the red wire, but before it gets there it runs through the Freon high pressure switch connector. Also check the APADS ground.
  5. Macktech689

    2004 mack ch fan need help!!

    The only way to remove the password is to flash and program the control module.
  6. Macktech689

    Mac cxu613 fan clutch

    The easiest way to check to see if the fan is capable of engaging is to disconnect it from the engine harness and run the engine over 1000 rpm. The fan should fully engage in around 10 seconds, if it doesn't replace the fan drive. Loss of voltage triggers a limp home mode, keep in mind the fan drive will rarely fully engage during normal operation 75 to 80% is normal.
  7. Macktech689

    Mp8 code

    The only thing I get from what you posted is it a engine fault, you'll need to hook up with diagnostic software to get a better fault code description.
  8. Macktech689

    Bull gear on mp8 engines

    There was no change to the flywheel housing when the staked idler gears were installed, removing the housing is no small job the back and bottom of the engine needs to come off. You can check the idler gear through the PTO cover at the top of the housing on the right side to see if it is loose, if it is you will also see where it's rubbing on the housing. The video you mentioned may have been of a MP-7. A good picture of the top of the housing would be helpful, a pic of the bottom won't show anything.
  9. Macktech689

    Mp7 2007 04 EPA Harness

    The harness for that engine runs in the $600 range I think, I don't buy them I replace them. I've replaced dozens of engine harnesses, it's not a bad job as far as I'm concerned. The worst part of the job on a 04 emission's MP-7 is getting the harness disconnected from the mass flow tube module behind the alternator bracket.
  10. Macktech689

    Engine Code

    SPN 105 is the intake manifold temperature sensor, you didn't mention what year your truck is. The earlier engines used 2 sensors one for pressure the other for temperature, the sensor is capable of doing both so newer engines only had 1 sensor. Regardless the temperature sensor is located in the back of the intake manifold. If you have a older engine with 2 sensors switch them and see if the fault goes away.
  11. Macktech689

    Fast idle with cruise control

    If you are unable to adjust the engine speed using the speed control switches it's possible that the function is not enabled in the VECU. PTT will need to be used to make parameter changes in the control module.
  12. I would start with checking the sensor 5V. supply, ground and signal voltage. Do it first at the sensor and if everything is OK check at the ECM connector, may be a wiring problem.
  13. Macktech689

    Bull gear on mp8 engines

    I can't help with the VIN, the pinning campaign was PI0785 and was issued in May 2102. You can check your trucks build date it's on the decal inside the drivers door jamb, you could also contact Mack to see if your truck was part of this campaign and whether it was already done. Another thing to look at is to see if a plug is installed in the top of the flywheel housing next to the crank sensor, the plug is put in after the pinning is done.
  14. Macktech689

    Bull gear on mp8 engines

    Double idler gear failures are not uncommon. Starting in 2010 the oil temperature was raised to 238 degrees and the hotter oil was causing the retainers to loosen, originally the retainers were installed with Loctite and not staked in place. After a rash of failures staking the retainers was put into production can't remember exactly when. There was a campaign to "pin" the retainers for a while, haven't done it in years, You could ask your dealer about it and see if they would be willing to do it for you. It's possible the gear in your engine has a staked retainer already.
  15. Could be a loss of module communication on J1939.

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